Holy means set apart
In the Bible, holy means set apart, belonging uniquely to God. God is not simply the greatest being among other beings. He is the Creator, while everything else is his creation. Moses celebrates this difference by asking who compares with the Lord in holiness (Exodus 15:11).
God’s holiness includes his majesty, power, faithfulness, justice, and beauty. He is completely unlike false gods made by human hands or shaped by human imagination. Nothing limits him, corrupts him, or puts him in anyone’s debt.
Who is like unto thee, O Lord, among the gods? who is like thee, glorious in holiness, fearful in praises, doing wonders?
Why say it three times?
When Isaiah saw the Lord in the temple, seraphim, heavenly servants, called out that God is holy three times (Isaiah 6:3). In Hebrew writing, repetition adds emphasis. Saying a word three times is a powerful way of declaring its fullness. God is not partly holy, or holy only on his best days. Holiness belongs perfectly to him.
John receives a closely related vision of living creatures around God’s throne, worshipping him day and night (Revelation 4:8). Both scenes join God’s holiness with his glory filling all creation. His holiness is not a cold distance. It is the blazing goodness of the One who reigns over all.
And one cried unto another, and said, Holy, holy, holy, is the Lord of hosts: the whole earth is full of his glory.
God is morally pure
God’s holiness also means he is wholly good. Evil does not come from his character, and he does not treat wrongdoing as harmless. Habakkuk says that God’s eyes are too pure to look favourably on evil (Habakkuk 1:13). That helps explain why Scripture speaks so seriously about sin. Sin damages people, rejects God’s good rule, and cannot simply be brushed aside.
Isaiah felt this sharply. Faced with God’s holiness, he recognised his own uncleanness and the brokenness around him (Isaiah 6:5). Most of us know something of that feeling. A glimpse of real goodness can make our mixed motives and selfish choices harder to ignore.
Holiness makes room for grace
Isaiah’s story does not end with shame. A seraph touches his lips with a coal from the altar, and Isaiah is told that his sin is taken away (Isaiah 6:6-7). The holy God is not indifferent to sin, but he is also the God who provides cleansing. His purity does not mean he refuses to come near people who need help.
For Christians, Jesus shows this most clearly. He gave himself to deal with sin so that people could be brought to God (1 Peter 3:18). God’s holiness calls for an honest response, not pretending we are fine. Yet it also gives solid hope: the God who reveals what is wrong is able to forgive, renew, and lead his people.
And the four beasts had each of them six wings about him; and they were full of eyes within: and they rest not day and night, saying, Holy, holy, holy, Lord God Almighty, which was, and is, and is to come.